Grains provide a rich source of proteins and complex carbohydrates, both of which are necessary ingredients for a well-balanced diet. In addition, grains may be deformed from their discrete shapes into a multitude of forms including flakes, shreds, flours and the like. Starch, composed of both amylose and amylopectin provides for formability of grains into ready-to-eat breakfast cereals, hot cereals, breads, and other baked goods.
Bran, a cereal grain fraction, is relatively low in starch. In the process of U.S. Pat. No. 4,500,558 to Fulger et al, bran is modified by extrusion so that it becomes more readily millable. According to U.S. Pat. No. 4,500,558, from 10 to 25% starch is naturally present or is added to the bran material, the starch functioning as a vapor-lock to build pressure and to coat the bran during extrusion.
Milled grains, cooked or otherwise, generally have a bland and undifferentiated taste. Many schemes have been conceived and protocols designed to treat cereal grains and render their taste sweeter, more complex and more differentiated.
The conversion of grain starches into smaller components has a long history. Hydrolysis of the long polysaccharide chains into shorter chains and monomers such as glucose and maltose may be performed by treating starches with dilute acids, dilute alkalis or by enzymatic catalyzed reactions.
Although there is some evidence for xylose isomerase activity in wheat germ, (Pubols, M. H., et al., Plant Physiology 38, 454 [1962]) and other higher plants (Bartfay, J., Nature 185, 924 [1960]), still, the enzyme would be expected to be denatured during cooking.
Formability and/or product breakage problems tend to arise where grain is altered such that a sufficient amount of maltose or glucose, i.e., dextrose, is produced in sweetening amounts for breakfast cereals. Starch is generally needed for its matrix forming abilities so the grain may be deformed, blended, and conformed into ready-to-eat end products such as shredded wheat, cereal flakes, and expanded or puffed cereals.
In U.S. Pat. No. 4,656,040 to Fulger et al a matrix forming ingredient which is either a modified bran fraction, a toasted ground germ fraction, or combination thereof is admixed with an enzymatically hydrolyzed endosperm fraction. The endosperm fraction, it is disclosed, contains approximately 95% of the starch of the whole grain and treating it alone, with alpha-amylase and glucoamylase, avoids off-flavor development.
Treatment of cereal grains and subcomponents therein with proteolytic enzymes is disclosed in U.S. Pat. Nos.: 1,178,039 to Wahl; 2,853,388 to Kiely; 3,157,513 to Allen et al.; 3,243,301 to Hesseltine et al.; 4,056,637 to Hagiwara et al. Japanese examples of such treatments are taught in: Japanese Patent Publication No. 53-62848, published June 5, 1978; and Japanese Patent Publication No. 57-47465, published Mar. 18, 1982.
In U.S. Pat. No. 1,178,039 a food product is prepared by maintaining a mixture of water and bran at a temperature within the range of 45.degree. C. to 50.degree. C. to produce lactic acid bacteria. The bacteria, it is taught, generate proteolytic enzymes that act on the proteins in the bran. Additionally, diastase, i.e., amylase, contained in the bran inverts gelatinized starch which is added to the mash. The product is used in the preparation of beverages.
U.S. Pat. No. 2,853,388 teaches a process for rendering cereal foods such as corn, rice, wheat, and oats amenable to rapid cooking. The process is carried out by reacting the grains with one or more proteolytic enzymes at 35.degree. C. to 50.degree. C. The cereal, it is taught, may be treated with the enzymes either before or after crushing of the grain.
U.S. Pat. No. 3,157,513 teaches the enzymatic treatment of cereal grains or flour derived from cereal grains to obtain an aqueous liquid material which contains soluble and colloidal partially digested proteins. Grain in finely divided condition is first digested with a proteolytic enzyme in an aqueous slurry to convert more than 50 percent of the protein content of the cereal. The bran and starch residual solids are separated to obtain a proteinaceous liquid. The sludge layer separated from the starch fraction may be subjected to gelatinization and then digested in the presence of amylolytic enzymes to convert the starch content to sugars. The sludge, it is taught, can be simultaneously reacted with proteolytic enzymes to further solubilize and convert any protein portion present.
U.S. Pat. No. 3,243,301 teaches the preparation of tempeh by mixing cereal grains such wheat, rice, and rye with a fungus which produces proteolytic and lipolytic enzymes. The mold, Rhizopus oligosporus, has the proprietary designation of NRRL 2710. This mold produces very little or no amylolytic enzymes, thereby avoiding the production of sugars and organic acids. The grains are cracked, soaked with water, inoculated and steamed according to the process.
U.S. Pat. No. 4,056,637 teaches a process for fermenting food products from a cereal germ with lactic acid bacteria. Here, a culture medium containing a water extract of a cereal germ is inoculated with lactic acid bacteria. The water extract is obtained by extracting the cereal germ with hot water in the presence of a starch hydrolase. The starch hydrolase, it is taught, may be used in conjunction with cellulases or proteases. Alpha-amylase, diastase and glucoamylase are taught as suitable hydrolases. The addition of the starch hydrolase, it is taught, leads to the formation of sugars which are required for lactic acid fermentation. The lactic acid fermented product may be dried under conditions which avoid thermal changes to the product. The dried products may be used as such or used as fortifying nutritive additives.
Japanese Publication No. 53-62848 teaches the preparation of a digestible nutritive liquid prepared by immersing a polished rice, rice with germs or a roughly round rice product into an enzyme solution for decomposing indigestible components such as cellulose and hemicellulose. The material is permitted to swell whereupon the solid material is separated from the enzyme solution. Water is then added followed by boiling to obtain a liquid food. The enzymes used, it is taught, may be cellulase, pectinase, or hemicellulase. A nutritive food, such as bean milk may be added with protease to the solid material which is separated from the enzyme solution.
Japanese Publication No. 57-47465 teaches the preparation of a cereal tea extract. In this process, cereal grains are heated at 110.degree. C. to 200.degree. C. to vaporize their undesirable flavors and to puff their albumin content. The heated cereal grains are impregnated with an aqueous solution containing at least one kind of enzyme selected from amylase, protease, and cellulase. The impregnated cereals are heat-dried at 50.degree. C. to 100.degree. C. and then roasted at 100.degree. C. to 170.degree. C. The heating, it is taught, causes puffing which allows impregnation of the enzyme solution into the cereal grains. However, none of the above cited references teach the production of shredded, flaked, or extruded cereals.
The production of cereal products which may be in shredded, flaked or extruded form by treatment of cereal grains with proteolytic enzymes is taught in U.S. Pat. Nos.: 976,332 to Anhaltzer; 1,541,263 to Hoffman et al.; 3,664,848 to Bedenk et al.; and 4,282,319 and 4,377,602 to Conrad.
U.S. Pat. No. 976,332 teaches making breakfast cereals from wheat, corn, rye or other grains by mixing flour with an aqueous solution of pepsin, i.e., a proteolytic enzyme. Here, dough is used to form a film which is then dried and roasted. A flavorant, including desiccated coffee and sugar, is added as a coating to the roasted flake.
U.S. Pat. No. 1,541,263 teaches defatting the germs of cereals such as wheat germ, maize germ or rice polishings, i.e., germ and bran material, cooking them to gelatinize the starch, and then treating them with malt, i.e., diastase enzyme, to convert the starch in the grain to maltose and dextrin. Also, proteolytic enzymes, e.g., papain, trypsin, pancreatin, and pepsin, are added singly or in combination. The dried product may be used as an ingredient in the preparation of bread or shredded or flaked cereals.
U.S. Pat. No. 3,664,848 teaches the preparation of a breakfast cereal by mixing a soy protein source, proteolytic enzymes and a pregelatinized grain to form a dough. The dough is used to form strands which are then pelletized. The pellets are then puffed. Extrusion and flaking are taught as well.
U.S. Pat. Nos. 4,282,319 and 4,377,602 teach processes for preparing, in situ, enzymatically hydrolyzed protein and starch products from whole grain. The processes comprise crushing whole grain and thereafter subjecting the crushed grain to an enzymatic treatment in an aqueous medium with an endopeptidase so as to transform substantially all of the water soluble proteins to water soluble protein products. The water soluble starch fraction in the remaining crushed grain is subjected to enzymatic treatment in an aqueous medium with at least one starch hydrolyzing enzyme to transform substantially all of the water and soluble starch fractions to water soluble degraded products of starch. The processes are preferably carried out below the gelatinization temperatures of the grain. Bran may be removed either before or after enzymatic treatment of the cereal. The final cereal product may be used as a nutrient in breakfast flakes. Sequential treatment with alpha-amylase, amyloglucosidase and isomerase to form fructose may be used to solubilize the starch. The pH at which the amyloglucosidase acts is used to control hydrolysis to maltose or glucose. In Example 22, production of a breakfast cereal product containing wheat syrup and bran is disclosed. The wheat bran is obtained by isolation from a crushed grain which has been enzymatically hydrolyzed with protease, amylase, and amyloglucosidase. (See Example 2.) Enzymatic treatment of substantially only bran in the production of a cereal is not taught.
In these processes for producing cereal products using proteolytic enzymes, a whole cereal grain or a bran fraction is not treated enzymatically so as to retain starch or high molecular weight dextrins for their matrix forming ability.
The enzymatic treatment of cereal grains using cellulase or a combination of alpha amylase, amyloglucosidase, and glucose isomerase are disclosed in U.S. Pat. Nos.: 4,069,103 to Muller; 4,089,745 to Antrim et al.; 4,247,636 to Schoenrock et al.; 4,292,331 to Ostre; 4,378,432 to Castelli et al.; 4,458,017 to Horwath et al.; and 4,501,814 to Schoenrock et al. Processes using starch attacking enzymes are also taught in European Patent Application No. 78,782 and Swiss Patent Publication No. 622,028, published Mar. 13, 1981.
U.S. Pat. No. 4,069,103 teaches a process for obtaining dextrose and dextrins from a proteinaceous starch product. The starch product is subjected to acid or enzymatic hydrolyses whereupon the proteins are separated from the sugar solution using an ultrafiltration method. High molecular weight soluble protein is recovered and then subjected to spray drying to obtain a high protein product. The sequential treatment of starch with an amylase, amyloglucosidase, and isomerase is also taught.
U.S. Pat. No. 4,089,745 teaches a process for enzymatic conversion of corn hull cellulose to glucose wherein corn hulls are treated with alkali to obtain three fractions and cellulose is converted enzymatically to glucose.
U.S. Pat. No. 4,247,636 teaches the production of a fructose sweetener from an impure starch source containing beta glucans. Here, impure flour and water are mixed and then treated with the enzyme beta glucanase to produce a slurry having a viscosity of less than about 1,000 centipoise. The slurry is then sequentially treated with alphaamylase, glucoamylase, and glucoisomerase. Conversion of starch solutions into high fructose sweeteners using a three-enzyme process is taught as old in the art.
U.S. Pat. No. 4,292,331 teaches a process for stabilizing and preserving harvested vegetables in an acidic environment located within a silo. The desired acidity is obtained by degradation of starch, complex carbohydrates, and fermentable carbohydrates. A mixture of bacteria and enzymes capable of degrading complex carbohydrates into fermentable sugars is used. Here, fermentable sugars are fermented into lactic acid by lactobacilli. Enzymes which may be used include a mixture of fungic amylases, amylases of bacterial origin, amyloglucosidases and hemi-cellulases. The enzymes may be supported on a cereal, preferably in a finely ground form. The starch contained in the support is added to the starch in the carbohydrates contained in the vegetables and is degraded into fermentable sugars. The process, it is taught, makes it possible to completely restrain all butyric fermentation.
U.S. Pat. No. 4,378,432 teaches the production of a sweetened aqueous liquor from a cellulose-containing vegetable substrate. Here, a vegetable substrate is treated with phosphoric acid under conditions causing hydrolysis of the cellulose contained within the substrate. Next, an enzyme is added to the resulting product to hydrolyze cellulose to form an additional amount of reducing sugars so as to obtain a sweetened aqueous liquor. Enzymes which hydrolyze cellulose and hemi-cellulose are used.
U.S. Pat. No. 4,458,017 teaches the preparation of fructose by liquefying starch with alpha-amylase, contacting the resulting liquefied starch with glucoamylase, and isomerizing at least part of the glucose to fructose using glucose-isomerase. All three enzymes are obtained from the same organism, i.e., Irpex mollis. References relating to the enzymatic conversion of glucose to fructose are listed in column 1, lines 40 to 56.
U.S. Pat. No. 4,501,814 teaches the production of a high fructose sweetener from an impure starch flour. The flour is subjected to enzymatic degradation in a sequence of steps which first liquefies, then saccharifies, then purifies the liquid starch. Substantially all the undissolved matter is removed from the slurry subsequent to initiation of the saccharification stage but prior to complete saccharification. Roughage, such as grain hulls, is removed mechanically prior to slurrying the impure starch flour. Beta-glucanse and alpha-amylase are added sequentially to the slurry to liquefy the starch. The production of high fructose corn syrups by treatment of starch solutions with alpha-amylase, glucoamylase, and glucoisomerase in sequential fashion is taught as old in the art. Several expired patents directed to such processes are listed at column 1, line 45 to column 2, line 15.
European Application No. 78,782 teaches the enzymatic treatment of whole cereal grains for the production of beer by a heat-technical wet processing method. Here, glucose is produced which reacts with proteins to form glucoproteins. The production of glucoproteins, it is taught, should be avoided because they are difficult to digest. Accordingly, alpha-amylase and ground cereal grains are added simultaneously to water having a temperature such that starch is only converted to soluble dextrins and oligosaccharides before inactivation of the enzyme by heat. Treatment of the starch with alpha-amylase at such a temperature, it is taught, avoids glucose production as well as the formation of sugar-protein compounds. The liquid phase which is obtained may be further treated to decompose the starch derivatives using amyloglucosidase and/or isomerase.
Swiss Pat. No. 622,028 teaches a process for producing foodstuffs having a desired level of sweetness obtained without the addition of sweeteners. Such products can be cocoa. The raw materials can be ground cocoa beans, boiled potatoes or boiled potato waste, or broken baker's wares. In a specific example, cocoa powder is treated with alpha-amylase, amyloglucosidase and isomerase. Fifty percent of the cocoa starch was converted to fructose. When the dispersion was dried, the resultant cocoa powder had 50 percent of the original starch converted to glucose and 50 percent to fructose. The starting materials are ground or mechanically manipulated so as to expose the starch thus destroying the integrity of the starting materials.
However, the products resulting from these enzymatic treatments with cellulase or alpha amylase, glucoamylase, and glucose isomerase are not cereals. Retention of starch for its matrix forming properties so as to provide formability of the enzymatically treated cereals is not taught in these references.
Enzymatic treatment of ground grains or grain fractions with sugar-producing enzymes in the preparation of cereal products is taught in U.S. Pat. Nos.: 1,172,270 to Franzie; 2,040,943 to Kang; 2,289,416 to Fine; 3,255,015 to Blanchon; 3,395,019 to Kviesitis; 3,930,027 to Kelly et al.; 3,950,543, to Buffa et al. and 4,311,714 to Goering et al.
In U.S. Pat. No. 1,172,270 a food product is produced by fermentation of ground, cooked rice or other cereals with a fruit extract or fruit such as banana. The starch within the rice is converted to a sugar.
U.S. Pat. No. 2,040,943 teaches preparing sweet tasting cereal foods by mixing rice, ground wheat, and ground malted barley, then boiling the mixture. After boiling, the mixture is simmered and liquid is recovered which is then boiled until thick. The liquid is then cooled and pulled. An analysis of the finished product shows the presence of sucrose, dextrins, and reducing sugars. (See the second column in the patent.)
U.S. Pat. No. 3,255,015 teaches the treatment of the envelope and cortical layer of cereal grains for the purpose of separating the enzymes and nutrients. Bran, it is taught, may be treated for release of enzymes, enzyme activators, oliogoelements and sugars. Here, an initial batch or charge consisting of the envelope and cortical layer of cereals are treated enzymatically so as to obtain a liquid rich in enzymes and other active substances. The liquid is continuously recycled so that the envelope and cortical layers of the cereal grains are subjected to continuous treatment. In the preferred embodiment, five parts water is mixed with one part ground bran. The aqueous bran mixture is then treated with pectinolytic enzymes obtained from fungi, bacteria or cereal brans. In one arrangement, a cellulose residue is strongly attacked by the enzymes contained in the plant tissues. The enzymes, cellulase and hemi-cellulase, are either added per se or after a preserving treatment. Food products such as cakes, oils rich in cellulose, fish waste, etc. are produced.
U.S. Pat. No. 3,395,019 teaches a process for making animal feed from oat hulls. Ground oat hulls are mixed with water in an amount of 50 to 70 percent by weight, followed by treatment with alkali and yeast or enzymes such as catalase, cellulase, and amylase. The treatment of the oat hulls, it is taught, increases the absorption capacity of the hulls for materials such as molasses, fish solubles and the like.
U.S. Pat. No. 3,930,027 teaches a process for making precooked dehydrated products. Here, gelatinized starch is reacted with amylase until complete hydrolysis occurs. Then, the hydrolyzed starch is slurried with some nonhydrolyzed starch such that a maltose concentration of about 14 percent, based upon the total weight of the slurry, is obtained. The concentration of maltose is critical, it is taught, for reducing susceptibility to caking. Reconstitution of the hydrated, flaked product results in a homogeneous smooth textured cereal mass.
U.S. Pat. No. 3,950,543 teaches a process for making weaning flour or baby foods. Here, a material such as flour, meal, grits and cereal is mixed with at least one high temperature resistant starch-hydrolyzing enzyme. The mixture is then heated in the range of 65.degree.-115.degree. and simultaneously extruded. The extrudate is fermented to a dextrin and reducing sugar concentration of 25 percent and 15 percent respectively, based on the initial starch content. The patent discloses a two-enzyme process, wherein the enzymes are alpha-amylase and glucoamylase.
U.S. Pat. No. 4,311,714 teaches a process for making protein products and maltose syrup from flour obtained from a waxy barley grain. Beta-glucans contained in barley starch solids are partially hydrolyzed. Proteins are released and starch is at least partially hydrolyzed to obtain maltose. One of the enzymes used in the hydrolysis is amylase. The barley starch solids which are treated with the enzyme have at least a portion of the protein solids removed from the starch. Use of a wax grain, it is taught, is critical because of amylopectin content. The beta-glucans are removed to facilitate working on the barley. Bran, a by-product, is separated from the grain and not subjected to the enzyme treatment.
However, in the processes of these patents, the enzymatically treated ground grains or grain fractions are not taught as being formed into flaked, shredded, or extruded cereals.
The production of instant breakfast cereals in powdered or flaked form involving the enzymatic treatment of ground grains or grain fractions with sugar producing enzymes is disclosed in U.S. Pat. Nos. 4,374,860 to Gasser et al and 4,438,150 to Gantwerker.
U.S. Pat. No. 4,374,860 teaches the baking of a readily water-miscible powdered amylaceous food product. Here, a mixture of materials such as coarse meal, fine flour, cereal starch, and water is cooked to cause gelatinization of the amylaceous material while liquification of the mixture is brought about by enzymatic hydrolyses. Additional amylaceous material is added to the mixture whereupon this second mixture is cooked to cause gelatinization. This second mixture is liquefied by enzymatic hydrolyses and then spray dried. The enzymatic hydrolysis employs alpha-amylase, amyloglucosidase or beta-amylase. Hydrolysis using amyloglucosidase without alpha-amylase is taught as being slower in starting but results in a higher degree of hydrolysis. The resultant product is a powder which is suitable for use in soups, acidic beverages or instant breakfasts. The process avoids expensive concentration steps and Maillard or carmelization reactions. The browning reactions, it is taught, occurs in known processes involving the production of instant flaked cereals where a paste or suspension of ground cereal is gelled and enzymatically hydrolyzed on a drying drum.
U.S. Pat. No. 4,438,150 teaches a process for making a dry, gelatinized cereal porridge product capable of being instantly prepared as a hot or cold food. Here, a gelatinized cereal flour slurry is subjected to mechanical shear of sufficient intensity and duration so as to reduce viscosity of the gelatinized cereal mixture. The patent teaches away from the use of enzymes to reduce viscosity because browning reactions between cereal protein and glucose, excessive flake product density, and production of a watery porridge upon reconstitution occur.
The enzymatic treatment of ground grains or grain fractions with sugar-producing enzymes in the production of a ready-to-eat (RTE) cereal in shredded,- flaked, or extruded form is disclosed in U.S. Pat. Nos.: 1,564,181 to Kellogg; 1,568,162 to Humphrey; and 4,431,674 and 4,435,430 to Fulger et al.
In U.S. Pat. No. 1,564,181 a bran food is prepared by mixing ground barley malt (a source of malt enzymes) with bran to convert bran carbohydrates to maltose or malt sugars. Winter wheat bran is taught as being preferred. Following enzymatic treatment, the mixture is cooked, dried, then shredded or flaked. Other enzymes may be substituted for the malt enzymes, it is taught. The dried bran is shredded at a moisture content of 10 percent or 20 percent. The shredded product is then preferably dried or toasted. Flaked products are produced by allowing the dried bran to stand and harden. Lumps are formed and then broken into smaller pieces. The pieces are then rolled into flakes and dried or toasted. The dried bran may be ground and then toasted or dried in powder form as well. Biscuits may be formed from the powdered or shredded product.
U.S. Pat. No. 1,568,162 teaches a process for making cereal which is a combination of a fruit pulp, e.g., apples, and a grain such as wheat. Yeast is added to produce fermentation of the starch although this action is limited to prevent conversion of carbohydrates to alcohols. Fruit pulp, sugar, yeast, and flour are mixed to form a dough.
The dough is left in a warm atmosphere for 30-40 minutes, then cooked. The dough is then formed into pieces using a die. The pieces are then dried, flaked and toasted.
U.S. Pat. Nos. 4,431,674 and 4,435,430 teach the preparation of enzyme-saccharified ready-to-eat breakfast cereals derived from whole cereal grains. The process comprises the steps of: (a) milling and separating a whole cereal grain to produce a germ fraction, a bran fraction and endosperm fraction; (b) enzymatically hydrolyzing from 15 to 75 percent by weight of the endosperm fraction; (c) modifying the bran fraction to improve its functionality; and (d) recombining the treated fractions to form a cereal dough. These patents teach that it is critical to treat bran fractions to improve functionality and that subjecting all of the cereal substances to enzymatic treatment makes it difficult to produce a dough of sufficient functionality. A dual simultaneous enzymatic reaction involving bacterial alpha-amylase and fungal glucoamylase is preferred. The recombined fractions may be formed into flakes and cut into shapes with a cookie cutter. They may also be combined with an endosperm or starch fraction then expanded.
In the production of these ready-to-eat cereals and instant breakfast products using sugar producing enzymes, enzymatic treatment so as to retain starch and high molecular weight dextrins for matrix forming ability while developing sweetness and taste complexity is not taught.
The enzymatic conversion of whole cereal grains with sugar producing enzymes in the preparation of cereal products is disclosed in: U.S. Pat. No. 2,310,028 to Gustavson; U.S. Pat. No. 2,555,235 to Huzenlaud; U.S. Pat. No. 2,627, 64 to Keahetian; U.S. Pat. No. 3,958,015 to Gay; U.S. Pat. No. 4,371,551 to Fulger et al and Japanese Patent Publication No. 37-1654.
U.S. Pat. No. 2,310,028 teaches a process for making canned cereal such as oatmeal, wheat porridge, or corn meal. Cereal such as steel-cut dry oat meal or rolled oats, is precooked with water. A diastase enzyme is added to the cooled mixture to digest the starch. The mixture is then heated to sterilization temperatures and then sealed. Typically, the oat porridge is stirred slowly while being digested by the added malt diastase enzymes for about two minutes at 126.degree. F. The temperature is raised to 149.degree. F. to stop enzymatic activity.
U.S. Pat. No. 2,555,235 teaches a process for enriching the endosperm of grain by applying a vacuum to the grain which is then steeped in an extract of grain or offal to add more vitamins and minerals. Steeping takes place at a temperature and pressure which promote enzymatic action. Diastase or other enzymes may be added to promote enzymatic action. The grain is then treated with live steam and dried for milling or packaging. A list of the enzymes present in the grains is enumerated in column 5 of the patent. The first five enzymes of the list include amylase, glucosido and fructosido saccharases as well as the glucosido and gluco maltases. Cellulase is also listed.
U.S. Pat. No. 2,627,464 teaches a process for making breakfast cereals such as baby food. Wheat is germinated until the sprouts reach a length of about one-half inch. The germination is stopped by drying the sprouts. The dried sprouts are then ground into flour which is then mixed with water to form a dough-like consistency. The dough is then slowly cooked. Enzymes, it is taught, develop in the grain during the germination stage. These enzymes act on the starch during slow cooking which occurs in the temperature range of 180.degree. F. to 200.degree. F. for as long as eight hours. After cooking, the product is canned for long term storage.
U.S. Pat. No. 3,958,015 teaches a process for treating plant materials to obtain an augmented high protein and low carbohydrate product. Plant materials having a high level of starch are treated with enzymes which modify the carbohydrates to forms assimilable by yeast. Metabolism by elementary yeast enriches the protein content over that of the starting material. The plant material may include partially or completely dehulled soybean, legume beans, cereals, roots and tube roots. The plant materials, which have or have not been thermally treated, dehulled, peeled, ground, crushed, or flattened are subjected to the simultaneous action of enzymes. The enzymes used are the amylases, pectinases, cellulases, invertases, and beta-glucanases. The treatment of fine flour obtained from dehulled small white beans with alpha-amylase, betaglucanase, amyloglucosidase, and invertase is taught in Example III. After treatment with yeast, the reducing sugar content is less than one percent in the final dried product.
U.S. Pat. No. 4,371,551 teaches producing a composition possessing a malt-like flavor from root cultures and the use of the composition in a foodstuff such as breakfast cereal. A cereal grain, it is taught, upon germination, produces starch splitting enzymes such as alpha- and beta-amylase. In the process of U.S. Pat. No. 4,371,551 the rootlets are cultured and contain highly concentrated malt-like flavors.
Japanese Patent Publication No. 37-1654 teaches a process for making auto-digestive cereals such a malts. The cereals are steamed after having their pH adjusted for enzymatic reactions. Enzymes are then added which have been treated so as to be active at less than 55.degree. C. An edible salt is then sprayed on the material which is then dried.
However, in these processes for producing cereal products by enzymatically converting whole cereal grains with sugar producing enzymes, forming enzymatically treated grains into ready-to-eat cereals in shredded, flaked, or extruded form is not taught.
Production of a ready-to-eat cereal in shredded or flaked form involving enzymatic treatment of whole cereal grains with sugar producing enzymes is disclosed in U.S. Pat. Nos.: 2,174,982 to Kellogg; 2,289,416 to Fine; and 4,254,150 to Fritze et al.
U.S. Pat. No. 2,174,982 teaches a process for making shredded or flaked cereal foods from cereal grains such as wheat, rye, corn or oats. Here, the whole grain is boiled in alkali to partially dissolve the bran coating. The grain is then washed to remove the alkali and then treated with malt to convert starch to dextrins. A flavoring substance is added to the wort, whereupon the wort is kept at 148.degree. F.-170.degree. F. to expand the grain and allow penetration of the flavoring substance. The material is then cooked under pressure, dried and either flaked or shredded. The moisture content of the material for shredding is 20 percent. The dextrins in the product, it is taught, make it crisper. U.S. Pat. No. 2,289,416 teaches a process for making cereal foods in flaked or shredded form from whole grains. Prior to enzymatic action, the whole grains are treated by rupturing of the bran coat and gelatinization of starch with heat. Following this pretreatment, enzymes are added directly to the whole grain. The enzymes, it is taught, act more rapidly on gelatinized starch. Malted grain is taught as an enzyme source. Efficient conversion of gelatinized starch is taught as being at a temperature of from 60.degree. C. to 70.degree. C. Bumping, it is taught, greatly increases the permeability of the endosperm which can be performed before or after the gelatinization step. The addition of enzyme to flour and to bumped grain prior to cooking is taught as resulting in no substantial conversion of starch to subcomponents. Malted barley flour and a diastase concentrate, i.e., an Aspergilius oryzae amylase preparation, are each used as enzyme sources. Maltose is the only specifically disclosed sugar which is produced by this process.
U.S. Pat. No. 4,254,150 teaches the production of cereal foods in flaked form. Here, starch, in situ, is converted to dextrose by enzymatic conversion. Whole grains or grains ground from coarse to medium-fine grist is mixed with water to form a mash with the grain fraction of the mash being 20 to 40 percent. The mash is allowed to swell whereupon alpha-amylase is added. The pH of the mash is adjusted. The mash is then heated in a steam injection cooker at a temperature in the range of 100.degree. C. to 110.degree. C. The mash is then passed through a tube type converter which is also maintained at a temperature to 100.degree. C. to 110.degree. C. At this point the starch is converted to maltodextrin. The enzyme amyloglucosidase is then added to the mash to effect the conversion of maltodextrin to dextrose. The mash is then dried on a single roll dryer to form a thermoplastic film. The film is cooled to make it friable and then comminuted to form flakes. Prior to drying the mash, bran or other additives may be added for the production of a fodder. The enzymatic degradation of the starch in the grain is achieved without separating the starch from the grain or from the other dry substances such as glutin, fibers, and husks.
In the production of these ready-to-eat cereals, the enzymatic treatment of the whole cereal grains with sugar producing enzymes is not taught as retaining starch and high molecular weight dextrins for their matrix forming properties while developing sweetness and taste complexity.
The present invention provides a process for the production of breakfast cereals which are enzymatically sweetened while retaining starch and high molecular weight dextrins for their matrix forming properties. In the present invention, the in situ production of fructose requires less starch conversion to achieve a desired level of sweetness. The production of fructose also provides enhanced, honey-like, graham, flavors and aromas in the breakfast cereals of the present invention. Reduced starch breakdown provides for improved formability of the enzymatically treated cereal grains into breakfast cereal shapes and improved shape retention at a given level of sweetness.